Dose Of Inactivated Polio Vaccine Research Articles

Immuno-persistence after the 4th and 5th dose of inactivated polio vaccines in school-aged children

ObjectiveThis study aimed to assess the long-term persistence of neutralising antibodies (nAb) titres and seroprotection proportions after the 4th and 5th doses of inactivated polio vaccine (IPV). MethodsSerum samples from 299 children in Hong Kong were collected and used to estimate the persistence of nAb titres and seroprotection proportions by neutralisation test. ResultsThe mean nAb titres against polioviruses type 1, 2 and 3 (PV1, PV2 and PV3) one month after receiving the 4th dose of IPV at 19 months of age were 2,068 (95% credible interval: 1,517 – 2,864), 4,705 (3,439 – 6,436) and 2,758 (1,894 – 4,086), but declined substantially in 4 years to 268 (222 – 325), 751 (630 – 900), and 411 (323 – 521), respectively. Administration of the 5th dose of IPV restored nAb titres among children aged 6-7 years, and the decline in nAb titres was slightly slower with the estimated mean titres of 355 (272 – 462), 538 (427 – 681), and 548 (378 – 786) against PV1, PV2, and PV3 at 4 years post the 5th dose. We estimated that the proportion of children who were seroprotected against PV1, PV2 and PV3 would drop below 90% at: (i) 8.2, 10.8, 8.7 years after the 4th dose; and (ii) 11.6, 11.2, 11.0 years after the 5th dose. ConclusionsThe results revealed the immuno-persistence after the 4th and 5th dose of IPV and highlighted the importance of completing immunization series to ensure high vaccination coverage, particularly among children in the developing countries affected by the COVID-19 pandemic.

Use of a fractional dose of inactivated polio vaccine (fIPV) to increase IPV coverage among children under 5 years of age in Somalia

BackgroundGlobal efforts reduced incidence of polio cases from 350,000 in 1988 to 22 cases in 2022 globally. There have been no wild poliovirus (WPV) cases seen in Somalia since August 2014. However, in 2017, there was a surge in the number of cases of circulating vaccine-derived poliovirus type 2 (cVDPV2), even with different intervention responses using monovalent oral polio vaccine type 2 (mOPV2). This study aimed to assess the use of fractional inactivated polio vaccine (fIPV), a smaller dose of the polio vaccine, equal to 1/5 of a standard dose, as an innovative polio vaccination delivery model, and identify the main opportunities for and challenges to the use of fIPV in the future for vaccinations.MethodsThe study used two designs: a quasi-experimental design used to pilot fIPV in five districts and a cross-sectional study using both quantitative and qualitative approaches to collect primary data. A simple random sampling method was used to select 2 out of the 5 pilot districts for household surveys to study 768 participants. Key informant interviews and focus-group discussions were used to collect data from key frontline health workers and health/immunization officials involved in the campaigns. Secondary data from the pilot campaigns were analysed, such as administrative pilot data, lot quality assurance sampling (LQAS) and post-campaign communication assessments.ResultsA total of 131,789 children aged 4–59 months were included for the pilot. Among these, 126,659 (96.1%) and 126,063 (95.6%) children were vaccinated in rounds 1 and 2, respectively. Out of the 768 households assessed, 99.9% had their children vaccinated. Nearly half of the few children who were not vaccinated were reported to be due to the parent of the child not being at home (48%). Ninety-seven percent of the qualitative study interviewees were satisfied with fIPV injection and recommended its use for routine immunization.ConclusionsThe study findings are promising in the use of fIPV in mass campaigns to realize better coverage and global polio eradication. fIPV will potentially be used by policymakers in the design of polio eradication campaigns that integrate the fIPV vaccine into routine or supplementary immunization.

Neutralizing anti-polio antibody titre in newborn babies in post-polio eradication period in Nigeria

BackgroundAccording to Polio Eradication and Endgame Strategic Plan 2019-2023 (PEESP), countries that achieved wild polio elimination is expected to replace oral polio vaccine (OPV) which has a risk of vaccine-derived poliovirus, Inactivated Polio Vaccine (IPV). It is important to determine the earliest time in the age of a child at which IPV could be introduced into the country’s routine immunization schedule for effectiveness especially as it concerns neutralizing effect of trans-placental transmitted antibodies which usually does not affect OPV. In this study, the level of poliovirus neutralizing antibody titre among neonates at birth was evaluated. MethodsA cross-sectional study of mother-baby pair. The serum level of the neutralizing Poliovirus antibody IgG titre was done by the Enzyme Linked Immunosorbent Assay (ELISA) technique. ResultsThere was 100% transfer of maternal passive antibodies to their babies. The mean poliovirus antibody titre among neonates was 21.8 IU/L which was above the neutralizing titre level. Most (85.7%) babies antibody level correlate positively with that of their mothers. ConclusionThe transferred maternal antibodies to the babies are still very high at birth, and capable of dampening the immunity of IPV if introduced early. Programme managers should evaluate the impact and benefit of given booster dose of IPV to pregnant mothers to increase the titre level in their babies. This will be very necessary when the OPV is withdrawn from the immunization schedule.

Evaluation of the immunization effectiveness of bOPV booster immunization and IPV revaccination

To provide a basis for further optimization of the polio sequential immunization schedule, this study evaluated the effectiveness of booster immunization with one dose of bivalent oral poliovirus vaccine (bOPV) at 48 months of age after different primary polio immunization schedules. At 48 months of age, one dose of bOPV was administered, and their poliovirus types 1–3 (PV1, PV2, and PV3, respectively)-specific neutralizing antibody levels were determined. Participants found to be negative for any type of PV-specific neutralizing antibody at 24, 36, or 48 months of age were re-vaccinated with inactivated polio vaccine (IPV). The 439 subjects who received a bOPV booster immunization at the age of 48 months had lower PV2-specific antibody levels compared with those who received IPV. One dose of IPV during basic polio immunization induced the lowest PV2-specific antibody levels. On the basis of our findings, to ensure that no less than 70% of the vaccinated have protection efficiency, we recommend the following: if basic immunization was conducted with 1IPV + 2bOPV (especially Sabin strain-based IPV), a booster immunization with IPV is recommended at 36 months of age, whereas if basic immunization was conducted with 2IPV + 1bOPV, a booster immunization with IPV is recommended at 48 months of age. A sequential immunization schedule of 2IPV + 1bOPV + 1IPV can not only maintain high levels of antibody against PV1 and PV3 but also increases immunity to PV2 and induces early intestinal mucosal immunity, with relatively good safety. Thus, this may be the best sequential immunization schedule for polio in countries or regions at high risk for polio.

Epidemiological survey and genetic characterization of type 3 vaccine-derived poliovirus isolated from a patient with four doses of inactivated polio vaccine in Henan Province, China

BackgroundVaccine-derived poliovirus (VDPV) is a potential threat to polio eradication because they can reintroduce into the general population and cause paralytic polio outbreaks, a phenomenon that has recently emerged as a prominent public health concern at the end of global polio eradication. This study aimed to describe the epidemiology and genetic characteristics of the first VDPV identified from a patient with acute flaccid paralysis (AFP), with four doses of inactivated polio vaccine immunization in Henan Province, China in 2017.MethodsThe patient was diagnosed with type 3 VDPV. Subsequently, a series of epidemiological approaches was implemented, including a retrospective search of AFP cases, rate of vaccination assessment, study of contacts, and supplementary immunization activities. Fecal samples were collected, viral isolation was performed, and the viral isolates were characterized using full-length genomic sequencing and bioinformatic analysis.ResultsPhylogenetic analysis showed that the viral isolates from the patient were different from other reported genetic clusters of type 3 VDPV worldwide. They were identified as a Sabin 3/Sabin 1 recombinant VDPV with a crossover site in the P2 region. Nucleotide substitutions, including U → C (472) and C → U (2493), have been identified, both of which are frequently observed as reversion mutations in neurovirulent type 3 poliovirus. A unique aspect of this case is that the patient had been vaccinated with four doses of inactive polio vaccine, and the serum neutralizing antibody for Sabin types 1 and 3 were 1∶16 and 1∶512, respectively. Thus, the patient was speculated to have been infected with type 3 VDPV, and the virus continued to replicate and be excreted for at least 41 d.ConclusionsThe existence of this kind of virus in human population is a serious risk and poses a severe challenge in maintaining a polio-free status in China. To the best of our knowledge, this is the first report of VDPV identified in the Henan province of China. Our results highlight the importance of maintaining a high-level vaccination rate and highly sensitive AFP case surveillance system in intercepting VDPV transmission.

A Comparison with Adverse Events Following Immunization Associated with Sabin-Strains and Salk-Strains Inactivated Polio Vaccines in Zhejiang Province, China.

Objectives: One dose of Sabin-strains inactivated polio vaccine (IPV) was introduced into the Chinese immunization program on 1 May 2016. This study aimed to evaluate the safety of Sabin-strains IPV and provide a comparison with conventional Salk-strains IPV. Methods: Adverse events following immunization (AEFI) records associated with Sabin-strains IPV and Salk-strains IPV were extracted from the national AEFI surveillance system (NAEFISS) from 1 May 2016 to 31 December 2020. The vaccination information on Sabin-strains IPV and Salk-strains IPV during the same period was obtained from the Zhejiang provincial immunization information system. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories and were compared between Sabin-strains IPV and Salk-strains IPV. Results: In total, 3,861,758 doses of Sabin-strains IPV and 1,018,604 doses of Salk-strains IPV were administered during the study period. The overall AEFI reporting rate for Sabin-strains IPV (3.96/10,000 doses) was significantly lower than that for Salk-strains IPV (5.03/10,000 doses) due to the reporting rate of the minor vaccine product-related reaction following Sabin-strains IPV was significantly lower than that for Salk-strains IPV (2.76/10,000 doses vs. 3.83/10,000 doses). The most frequently reported symptoms/signs were fever, induration/swelling, and rash/urticaria. The most frequently reported serious AEFI with a causal relationship was febrile convulsion, with the reporting rates of 0.10/10,000 doses for Sabin-strains IPV and 0.08/10,000 doses for Salk-strains IPV. No significant difference was found in the reporting rates of the other serious AEFI between the two types of IPV. Conclusion: Most of the AEFI following Sabin-strains IPV and Salk-strains IPV were mild and common adverse reactions. The reporting rate of serious AEFI was not significantly different between Sabin-strains IPV and Salk-strains IPV. Sabin-strains IPV had a favorable safety profile and could be widely used.

A National Cross-Sectional Study from the Republic of Kosovo on Lot Quality Assurance Sampling (LQAS) to Evaluate the Vaccination Status of Children Between 12 and 24 Months of Age During 2018 to 2020

BackgroundIn the Republic of Kosovo, full vaccination status in children under age 2 years includes: 1 dose of Bacillus Calmette-Guérin (BCG) hepatitis B virus (HBV) vaccine; 3 doses of diphtheria, tetanus, pertussis, hepatitis B, polio, and Haemophilus influenzae type b (DTaP-HB-IPV-Hib) vaccine; 3 doses of inactivated polio vaccine (IPV); and 1 dose of measles, mumps, and rubella (MMR) vaccine. Lot quality assurance sampling (LQAS) is a method used to assess the performance of health quality indicators.Material/MethodsA national cross-sectional study with children aged between 12 and 24 months from Kosovo was performed between 2018 and 2020. The vaccination status of children was assessed with lot quality assurance sampling (LQAS) using randomized samples.ResultsAmong 430 children, more than 90% had completed the full immunization schedule. Delays in children’s immunizations were observed. Most vaccinations showed short delays of less than 1 month, followed by delays of up to 3 months. The main reason for vaccination delay was the COVID-19 pandemic, following by child’s illness at the scheduled time of vaccination or the parents were too busy to take the child to the vaccination site. Meanwhile, child age was the only parameter that showed difference among non-vaccinated and fully vaccinated (P<0.001).ConclusionsLQAS analysis showed that between 2018 and 2020 lack of full immunization was due to delay caused by the parent not taking the child to the vaccination site, which may be prevented by improving information given to parents and the use of vaccination reminders.

Inferring Numbers of Wild Poliovirus Excretors Using Quantitative Environmental Surveillance.

Response to and monitoring of viral outbreaks can be efficiently focused when rapid, quantitative, kinetic information provides the location and the number of infected individuals. Environmental surveillance traditionally provides information on location of populations with contagious, infected individuals since infectious poliovirus is excreted whether infections are asymptomatic or symptomatic. Here, we describe development of rapid (1 week turnaround time, TAT), quantitative RT-PCR of poliovirus RNA extracted directly from concentrated environmental surveillance samples to infer the number of infected individuals excreting poliovirus. The quantitation method was validated using data from vaccination with bivalent oral polio vaccine (bOPV). The method was then applied to infer the weekly number of excreters in a large, sustained, asymptomatic outbreak of wild type 1 poliovirus in Israel (2013) in a population where >90% of the individuals received three doses of inactivated polio vaccine (IPV). Evidence-based intervention strategies were based on the short TAT for direct quantitative detection. Furthermore, a TAT shorter than the duration of poliovirus excretion allowed resampling of infected individuals. Finally, the method documented absence of infections after successful intervention of the asymptomatic outbreak. The methodologies described here can be applied to outbreaks of other excreted viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), where there are (1) significant numbers of asymptomatic infections; (2) long incubation times during which infectious virus is excreted; and (3) limited resources, facilities, and manpower that restrict the number of individuals who can be tested and re-tested.

Análisis económico de las vacunas del primer año de vida con componente pertussis en el contexto de la ini-ciativa mundial de erradicación de la poliomielitis en Argentina

Background Global Polio Eradication Initiative promotes the introduction of inactivated polio vaccine (IPV) in its programs, with withdrawal of Sabin (bOPV). There is no an economic analysis of the investment related to the incorporation of IPV vaccines together with a whole cell Bordetella pertussis vaccine or combined with acellular hexavalent. Aim An economic model that compares different vaccination schemes for the prevention of polio and pertussis in the first year of life was carried out. Methods Four vaccination scenarios for the primary scheme based on Argentina demographic and costs data were developed: - Scenario 1 (base case): two doses of IPV, one dose of bOPV and three doses of pentavalent (DTwP-HepB-Hib) vaccine; - Scenario 2: three doses of IPV plus three doses of pentavalent; - Scenario 3: three doses of hexavalent; - Scenario 4: two doses of hexavalent plus one dose of pentavalent plus IPV. Results The incremental cost based on scenario 1 was USD 3.716.671; 19.696.668 and 14.383.341 for scenarios 2, 3 and 4 respectively. In terms of reactogenicity savings was -14.178.240 compared base case with scenario 3. Discussion Full IPV introduction investment and costs associated were modified according to the type of vaccine and reactogenicity related with the B. pertussis component.

Immunogenicity of sequential poliovirus vaccination schedules with different strains of poliomyelitis vaccines in Chongqing, China: a cross-sectional survey

ABSTRACT A new vaccination schedule with one dose of inactivated polio vaccine (IPV) followed by three doses of bivalent oral attenuated live polio vaccine (bOPV) was introduced in China in 2016. Both Sabin IPV (sIPV) and Salk IPV (wIPV) sequentially with bOPV were accepted in the Chinese routine vaccination schedule. We intended to assess the immunogenicity of the current primary schedule (s/wIPV-bOPV-bOPV) and the schedule in the early stage of the switch (tOPV-bOPV-bOPV), and compare immunogenicity between the groups with different polio virus strains. Healthy infants aged 60–89 days were recruited in hospitals in Chongqing. Infants were assigned to one of three treatments (tOPV-bOPV-bOPV, sIPV-bOPV-bOPV or wIPV-bOPV-bOPV) by enrollment time. Polio neutralizing antibody (NA) assays were conducted to assess immunity. 1027 eligible infants were enrolled. Over 95% seroprotection rates against type I poliovirus (PV1) and type III poliovirus (PV3) were observed in all groups. Infants who received tOPV-bOPV-bOPV had higher antibody titers against type II poliovirus (PV2) than did the IPV-bOPV-bOPV. The geometric mean titers (GMTs) of PV2 were only ~20 in the IPV-bOPV-bOPV. GMTs of PV1 were higher than PV3 in s/wIPV-bOPV-bOPV. The primary schedule of s/wIPV-bOPV-bOPV is insufficient to protect children against PV2, and the NA titer to PV3 is lower. Higher antibody responses were induced in sIPV-bOPV-bOPV than that in wIPV-bOPV-bOPV. Supplementary vaccination with one dose of IPV is necessary for children who had no tOPV immune history or had only one IPV to induce higher levels of immunity against PV2 and PV3.

Sero-survey of polio antibodies and quality of acute flaccid paralysis surveillance in Chongqing, China: A cross-sectional study.

Serums were collected from people to assess whether polio immunity level was high enough to satisfy the polio vaccine immunization switch in Chongqing.People in 7 age groups (<1 year, 1–2 years, 3–4 years, 5–6 years, 7–14 years, 15–19 years, ≧20 years) were randomly selected in 3 areas by different geographical features in 2015. Peripheral venous blood samples were obtained and assays to detect poliovirus (PV) –neutralizing antibodies were performed. Acute flaccid paralysis (AFP) data was collected from 2012 to 2016 in Chongqing to evaluate the performance of AFP surveillance system by indicator analysis.A total of 636 people were tested for PV neutralization antibodies (NA). Overall NA seroprevalence for PV1, PV2 and PV3 were 93.40%, 96.38% and 91.82%, and geometric mean titers (GMTs) were 61.14, 66.78 and 21.47, respectively. GMTs and NA seroprevalence for PV1, PV2 and PV3 in older people were lower than young people. There were significant differences in seroprevalences of PV1 and PV3 among geographic areas (P < .05) in Chongqing.High seroprevalence for PV1, PV2, and PV3 and qualified capability for monitoring AFP cases showed that the polio eradication program has made positive achievements in Chongqing and established a stable base for a polio vaccine immunization switch. Nevertheless, GMTs were negatively associated with age in the geographic districts with poor economical features, which will increase the risk of emergence of vaccine-derived PV after polio vaccine switch. More than 1 dose of inactivated polio vaccine should be introduced into the polio vaccine schedule, and the supplementary immunization of polio should still be annually carried out after polio vaccine switch, especially among elder children and the adults.

Current regional consensus recommendations on infant vaccination of the Latin American pediatric infectious diseases society (SLIPE)

ABSTRACT Introduction The 1st Regional Experts on Infant Vaccination (REIV) meeting generated updated consensus recommendations to improve the control of various major vaccine preventable diseases (VPD) in Latin America. Areas covered Workshops highlighted recent changes in immunization schedules within the region, experience of countries incorporating combined acellular pertussis vaccines schedules and parenteral inactivated polio vaccine (IPV). The need to definitively replace oral polio vaccine (OPV) by IPV, and potential benefits of introducing new combined vaccines, were extensively discussed. Expert opinion REIV strongly advised immediate adoption of either complete IPV schedules for all Latin America or schedules including at least two initial doses of IPV. Use of fractional doses of intradermally administered IPV (fIPV ID) was not recommended due to lower immunogenicity, lack of evidence on long-term protection, and technical difficulty to implement. Routine pertussis vaccination of pregnant women in addition to health workers of neonatology units and any previously unimmunized parent was encouraged. Administration of HBV vaccine to newborns within the first 24 hours of life, and then at 2, 4, and 6 months, and of a booster dose of conjugate Hib vaccine at age 12 through 15 months, was also recommended. Incorporation of combined vaccines (CV) was considered potentially advantageous.

Immunity and field efficacy of type 2-containing polio vaccines after cessation of trivalent oral polio vaccine: A population-based serological study in Pakistan

BackgroundIn Pakistan and other countries using oral polio vaccine (OPV), immunity to type 2 poliovirus is now maintained by a single dose of inactivated polio vaccine (IPV) in routine immunization, supplemented in outbreak settings by monovalent OPV type 2 (mOPV2) and IPV. While well-studied in clinical trials, population protection against poliovirus type 2 achieved in routine and outbreak settings is generally unknown. MethodsWe conducted two phases of a population-based serological survey of 7940 children aged 6–11 months old, between November 2016 and October 2017 from 13 polio high-risk locations in Pakistan. ResultsType 2 seroprevalence was 50% among children born after trivalent OPV (tOPV) withdrawal (April 2016), with heterogeneity across survey areas. Supplementary immunization activities (SIAs) with mOPV2 followed by IPV improved population immunity, varying from 89% in Pishin to 64% in Killa Abdullah, with little observed marginal benefit of subsequent campaigns. In the other high-risk districts surveyed, a single SIA with IPV was conducted and appeared to improve immunity to 57% in Karachi to 84% in Khyber. ConclusionsOur study documents declining population immunity following trivalent OPV withdrawal in Pakistan, and wide heterogeneity in the population impact of supplementary immunization campaigns. Differences between areas, attributable to vaccination campaign coverage, were far more important for type 2 humoral immunity than the number of vaccination campaigns or vaccines used. This emphasizes the importance of immunization campaign coverage for type 2 outbreak response in the final stages of polio eradication. Given the declining type 2 immunity in new birth cohorts it is also recommended that 2 or more doses of IPV should be introduced in the routine immunization program of Pakistan.

How does an intradermal fractional dose compare with an intramuscular full dose of inactivated polio vaccine in children?

How does an intradermal fractional dose compare with an intramuscular full dose of inactivated polio vaccine in children?

Equivalent schedules of intradermal fractional dose versus intramuscular full dose of inactivated polio vaccine for prevention of poliomyelitis.

Poliomyelitis is a debilitating and deadly infection. Despite exponential growth in medical science, there is still no cure for the disease, which is caused by three types of wild polioviruses: types 1, 2, and 3. According to the Global Polio Eradication Initiative (GPEI), wild poliovirus is still in circulation in three countries, and fresh cases have been reported even in the year 2018. Due to the administration of live vaccines, the risk for vaccine-derived poliovirus (VDPV) is high in areas that are free from wild polioviruses. This is evident based on the fact that VDPV caused 20 outbreaks between 2000 and 2011. Recent recommendations from the World Health Organization favoured the inclusion of inactivated poliovirus vaccine (IPV) in the global immunisation schedule. IPV can be delivered in two ways: intramuscularly and intradermally. IPV was previously administered intramuscularly, but shortages in vaccine supplies, coupled with the higher costs of the vaccines, led to the innovation of delivering a fractional dose (one-fifth) of IPV intradermally. However, there is uncertainty regarding the efficacy, immunogenicity, and safety of an intradermal, fractional dose of IPV compared to an intramuscular, full dose of IPV. To compare the immunogenicity and efficacy of an inactivated poliovirus vaccine (IPV) in equivalent immunisation schedules using fractional-dose IPV given via the intradermal route versus full-dose IPV given via the intramuscular route. We searched CENTRAL, MEDLINE, Embase, 10 other databases, and two trial registers up to February 2019. We also searched the GPEI website and scanned the bibliographies of key studies and reviews in order to identify any additional published and unpublished trials in this area not captured by our electronic searches. Randomised controlled trials (RCTs) and quasi-RCTs of healthy individuals of any age who are eligible for immunisation with IPV, comparing intradermal fractional-dose (one-fifth) IPV to intramuscular full-dose IPV. We used standard methodological procedures expected by Cochrane. We included 13 RCTs involving a total of 7292 participants, both children (n = 6402) and adults (n = 890). Nine studies were conducted in middle-income countries, three studies in high-income countries, and only one study in a low-income country. Five studies did not report methods of randomisation, and one study failed to conceal the allocations. Eleven studies did not blind participants, and six studies did not blind outcome assessments. Two studies had high attrition rates, and one study selectively reported the results. Three studies were funded by pharmaceutical companies. Paralytic poliomyelitis. No study reported data on this outcome. Seroconversion rates. These were significantly higher for all three types of wild poliovirus for children given intramuscular full-dose IPV after a single primary dose and two primary doses, but only significantly higher for type two wild poliovirus given intramuscularly after three primary doses: • dose one (six studies): poliovirus type 1 (odds ratio (OR) 0.30, 95% confidence interval (CI) 0.22 to 0.41; 2570 children); poliovirus type 2 (OR 0.43, 95% CI 0.31 to 0.60; 2567 children); poliovirus type 3 (OR 0.19, 95% CI 0.12 to 0.30; 2571 children); • dose two (three studies): poliovirus type 1 (OR 0.23, 95% CI 0.16 to 0.33; 981 children); poliovirus type 2 (OR 0.41, 95% CI 0.28 to 0.60; 853 children); and poliovirus type 3 (OR 0.12, 95% CI 0.07 to 0.22; 855 children); and • dose three (three studies): poliovirus type 1 (OR 0.45, 95% CI 0.07 to 3.15; 973 children); poliovirus type 2 (OR 0.34, 95% CI 0.19 to 0.63; 973 children); and poliovirus type 3 (OR 0.18, 95% CI 0.01 to 2.58; 973 children). Using the GRADE approach, we rated the certainty of the evidence as low or very low for seroconversion rate (after a single, two, or three primary doses) for all three poliovirus types due to significant risk of bias, heterogeneity, and indirectness in applicability/generalisability. Geometric mean titres. No study reported mean antibody titres. Median antibody titres were higher for intramuscular full-dose IPV (7 studies with 4887 children); although these studies also reported a rise in antibody titres in the intradermal group, none reported the duration for which the titres remained high. Any vaccine-related adverse event. Five studies (2217 children) reported more adverse events, such as fever and redness, in the intradermal group, whilst two studies (1904 children) reported more adverse events in the intramuscular group. There is low- and very low-certainty evidence that intramuscular full-dose IPV may result in a slight increase in seroconversion rates for all three types of wild poliovirus, compared with intradermal fractional-dose IPV. We are uncertain whether intradermal fractional-dose (one-fifth) IPV has better protective effects and causes fewer adverse events in children than intramuscular full-dose IPV.

Sequential inactivated (IPV) and live oral (OPV) poliovirus vaccines for preventing poliomyelitis.

Sequential inactivated (IPV) and live oral (OPV) poliovirus vaccines for preventing poliomyelitis.

Intestinal antibody responses to a live oral poliovirus vaccine challenge among adults previously immunized with inactivated polio vaccine in Sweden

BackgroundOur understanding of the acquisition of intestinal mucosal immunity and the control of poliovirus replication and transmission in later life is still emerging.MethodsAs part of a 2011 randomised, blinded, placebo-controlled...

Protocol for a systematic review and meta-analysis of fractional dose compared with standard dose inactivated polio vaccination in children

IntroductionWHO recommends the introduction of at least one single dose of inactivated polio vaccine (IPV) in routine immunisation schedules. Thus, there has been an increased demand and concurrent supply shortages...

Remarks on the possibility of introducing the fractionated dose of the inactivated poliomyelitis vaccine in the Latin American Child Immunization Schedule.

Given that the last notified case of poliomyelitis due to wild poliovirus type 2 was in 1999, in 2012, the Strategic Advisory Group of Experts on Immunization (SAGE) of the World Health Organization (WHO) recommended the withdrawal of the type 2 component of oral polio vaccine (OPV) and the introduction of a bivalent OPV (bOPV) in all countries by 2016. WHO recommended also that the withdrawal should be preceded by the introduction of at least one dose of inactivated poliovirus vaccine (IPV) in routine immunization schedules. The introduction of IPV prior to the change of the bOPV in 2016 to trivalent OPV (tOPV) was based on the concept of ensuring that a substantial proportion of the population would be protected against type 2 polio after the removal of the type 2 OPV. However, the world's two producers of IPV (Bilthoven Biologicals and Sanofi) have faced problems in the production of this vaccine and therefore reported a reduction of the global supply of IPV. In response to the potential shortage of IPV, at a meeting held on March 10 2017, the SAGE and Technical Advisory Group (TAG) of the Pan American Health Organization (PAHO) urged the countries in the Latin American region to replace the routine administration of the full doses of inactivated polio vaccine (IPV-C) in the immunization schedule (administered by intramuscular route), administering a fraction of the full dose in two intradermal shots (IPV-f). The possibility of this strategy was analyzed by opinion leaders convened by the Paraguayan Society of Pediatrics with the support of the Latin American Society of Pediatric Infectious Diseases (SLIPE) and Latin American Association of Pediatrics (ALAPE). This document presents the results of the discussion.

Lack of immune interference between inactivated polio vaccine and inactivated rotavirus vaccine co-administered by intramuscular injection in two animal species

A parenteral inactivated rotavirus vaccine (IRV) in development could address three problems with current live oral rotavirus vaccines (ORV): their lower efficacy in low and middle-income countries (LMICs), lingering concerns about their association with intussusception, and their requirement for a separate supply chain with large volume cold storage. Adding a new parenteral IRV to the current schedule of childhood immunizations would be more acceptable if it could be combined with another injectable vaccine such as inactivated polio vaccine (IPV). Current plans for polio eradication call for phasing out oral polio vaccine (OPV) and transitioning to IPV, initially in LMICs as a single dose booster after two doses of OPV and ultimately as a two dose schedule. Today in many LMICs, IPV is administered as a standalone vaccine, which involves a separate cold chain and is relatively costly. We therefore tested in two animal models formulations of IPV with IRV to determine whether co-administration might interfere with the immune response to each product and spare antigen dose for both vaccines. Our results demonstrate that IRV when adjuvanted with alum and administered alone or in combination with IPV did not impair the immune responses to either rotavirus or poliovirus serotypes 1, 2 and 3. Similarly, IPV when formulated and administered alone or together with IRV induced comparable levels of neutralizing antibody to poliovirus type 1, 2 and 3. Furthermore, comparable antibody titers were observed in animals vaccinated with low, middle or high dose of IPV or IRV in combination. This dose sparing and the lack of interference between IPV and IRV administered together represent another step to support the further development of this novel combination vaccine for children.